Modelling of Yeast Mating Reveals Robustness Strategies for Cell-Cell Interactions
Fig 3
Computer simulations of mating efficiency.
(A) Schematic of determining mating efficiency. In the simulation on the left, the tips marked by gray and black dots (polarisomes) of the two projections fall within a distance threshold (see Methods) so that the mating is considered successful. In the simulation on the right, the tips do not pass close enough to one another by the end of the simulation, and so the mating is deemed unsuccessful. (B) Faster and slower boundary velocities yielded similar mating trajectories. We ran simulations at two different boundary velocities (Vamp = 0.0001 and Vamp = 0.0002 μm/s). A plot of the distance between polarisomes of mating partners as a function of time is shown for a sample simulation. The plots are similar except the slower velocity took approximately twice as long to mate. (C) Direction plots for different boundary velocities and shorter cell-to-cell distance. In this plot each data circle represents one mating simulation. The average direction of each projection is plotted on the x-axis for the α-cell, and y-axis for the a-cell. The projections are toward one another when the data point lies along the diagonal line (i.e. top right and bottom left quadrants). We show the direction plots for the default simulation parameters (V = 0.0002 μm/s, left), slow boundary simulation (V = 0.0001 μm/s, middle), and close-cell positions (cell-to-cell distance = 2.5 μm instead of 4 μm, right). The mating efficiencies were similar for all three simulations. (D) Average mating time of successful matings under different simulation conditions same as in (C). Each bar represents the average time (± standard deviation) for successful mating. We performed 20 simulations for each condition, and the numbers of successful matings for default, slow and close parameters are 15, 17 and 16 respectively.